The Farpool: Diaspora

: In the early 23rd century, an exploratory mission is sent to Europa to examine what may lie in its sub-ice ocean. But contact with the mission is lost and a rescue mission is planned.
Charley Meyer, an officer in the Farpool Service and granddaughter of Chase and Angie Meyer (from The Farpool) is given command of the rescue mission. She becomes more than usually motivated upon learning that her one-time boyfriend Reynaldo Diaz was aboard the lost ship.
However, the Ponkti water clan of the Sea People also have designs on Europa as another world their own people can occupy and exploit. The Ponkti mean to keep humans away from Europa. When the rescue mission is fired upon and Charley realizes the Ponkti are behind the attack, a vicious struggle for the Jovian moon ensues and Charley and her crew are captured and imprisoned in an under-ice base run by the Ponkti.
Unknown to the humans, the Ponkti have made contact with an alien presence existing in Europa’s deep ocean. But instead of exploiting this alien presence, the Ponkti and their base come under attack from the aliens. Their Ponkti captors are killed but Charley and her crew escape to the surface, where they must hike across the icescape through severe radiation fields to a temporary farpool corridor set up for them.
Charley and Reynaldo make it to the farpool but through a navigation error wind up on Earth hundreds of years in the future. The Earth is completely flooded. Billions have died. And the same alien presence encountered on Europa is now moving into the outer solar system, consuming all in its path.
Through a newly created, long-range farpool called the Expool, Charley and Rey agree to make a test flight to a habitable world in the Trappist-1 star system. But before they can make it back, hundreds of desperate refugees from Earth also come through. Now seemingly stuck on this distant world, Charley and Rey must decide: should they stay and try to make a life on the world of Trappist-1e? Or should they chance one more trip through a rapidly deteriorating Expool and try to make it back to Earth?
Unknown to Reynaldo and the others, Charley intends to make one final trip. But this one won’t be back to a flooded, threatened Earth. Instead, the trip she wants to make will lead to adventures scarcely imaginable, a final mission vital to the survival of the human race.
Seventh title in The Farpool Stories.